Art of cracking hydrocarbons



L. LINK pri 29, 1930.

. ART OF CRACKING HYDROCARBONS Filed May 28, 1923 Patented Apr. 29, 1930 LOUIS LINK, OF BATON ROUGE, LOUISIANA, ASSIGNOR TO STANDARD OIL `DEVELOP- MENT COMPANY, A CORPORATION OF DELAWARE ART OF CRACKING EYDROCARBONS Application filed May 28,

rlhis invention relates to the art of pyrolytic conversion of hydrocarbons to lower boiling products and will be fully understood from the following description taken in connection with the accompanying drawing which represents diagrammatically a form of apparatus contemplated in the invention.

Referring more particularly to the drawing, the reference character 1 designates a distilling vessel of suitable construction, for example, a shell still such as is customarily used for running crude oil to coke. F rom a tower or other vapor dome 2 on the still a vapor line 3 leads to a fractional condensing tower 4. From this in turn a vapor line 5 leads to. a second tower` 6 and a vapor line 7 thence to a further tower 8, a vapor line 9 thence to a further tower 10, and a vapor line 11 thence to a further tower 12. A vapor line 13 from the last tower connects through a water cooled condenser coil 14 to a receiver 15. Although five towers are shown in the layout illustrated, the precise number may of course be varied in accordance with the particular kind of stock to be run and the general preference of the constructor. From the bottom of each tower a valved line 16 leads to a return line 17 connecting into the still. A branch 18 from the bottom line 16 of the first tower leads through a water cooled condenser coil 19 to a receiver 20, and similar branches 21, 22, 23 and 24 lead from the respective bottom lines of the remaining fractional condensing towers through corresponding water cooled condensing coils 25, 26,

27 and 28 to receivers 29, 30, 31 and 32 respectively. From the bottom lines of the iirst two towers valved connections 33 and 34 converge to an accumulator tank 35 and from the remaining fractional condensing towers similar valved connections 36, 37, and 38 converge to an accumulator tank 39. A line 4() with a pump 41 leads from the tank 35 to a cracking passageway 42 of suitable construction, and a line 43 having a pump 44 leads to a suitable cracking passage-way .45.v Discharge lines 46 and 47 from these cracking passage-ways converge to an inlet pipe 48 placed along the bottom of the still 1. The pipe 48 is perforated on its lower side preferablv with staggered 1923. Serial No. 641,825.

holes which are directed toward the floor of the still. A connection 49 on the discharge lines from the cracking passage-ways is ar ranged to lead to other stills if desired.

The precise construction of the Cracking passage-ways or zones may vary as desired.

ln general, an advantageous construction is a series of parallel tubes having end connections from tube to tube and row to row so as to aord a consecutive path, the tubes being mounted in a suitable heating chamber. If desired the final portion of the cracking passage-way vmay be enlarged, taking even the form of a drum with inlet at one end and outlet toward the other.

Assuming the plant in operation, oil to be cracked, for example a crude petroleum, is introduced into the still 1 through a charging line 50, and being distilled vapors rise and pass off by vapor line 3 to the fractional condensers. At the beginning condensates forming in the earlier condensers showing a gravity suitable for gasoline or kerosene may be run direct through the bottom lines to the condensing coils and receivers 20, etc. As the gravity of the stream from the earlier condensers becomes too`heavy for gasoline and kerosene for example, the streams are diverted by a suitable manipulation of the valves in the bottom lines so as to enter the accumulator tank 35. In like manner, the streams from the condensers 8, 10 and 12 are sent according to their gravity either into the iinal receivers or if heavier than the predetermined gravity, then into the accumulator tank 39. It will be seen that the comprehensive system of connections from the fractional condensers makes possible a diversion of the stream from any given condenser in accordance with the requirements as based upon the gravity showing at any given time, and the accumulator tanks function to receive fractions which are heavier than the predetermined limit desired for the final receivers 20, etc. If the accumulator tanks 35 and 39 be heat insulated, a saving of heat for the system as a whole may be eected. The line 17 permits of the diversion of condensates directly back to the still at any time that such proceeding be desired The heavier condensate from tank 35 is now drawn and passed through the cracking zone 42 and discharged through perforated pipe 48 in the bottom` of the still. In like manner heavier condensate from the tank 39 is passed through the cracking zone 45A and on to discharge by the pipe 48 into the still. It will be seen that the provision of two accumulator tanks enables the separate handling of heavier condensates of different character so that each may be subjected in its cracking passageway to the particular temperature and pressure best adapted for such condensate, and it will be understood that the invention is not restricted to the provision of two accumulator tanks as illustrated but contemplates one such tank or more in accordance with the nicety with which it is desired to separately handle the heavier condensate fractions for cracking. It will be understood also that the number of cracking passage-ways may likewise vary, one or more being provided as desired.

Having traversed the cracking passageway under appropriate temperature and pressure conditions, the hydrocarbons discharge through the perforated pipe 48 into the bottom of still l and the distillation process in this still is carried on until all vaporizable constituents have been driven off and vproperly cared for with a view to production of light distillate; and only coke remains in the still. y

If desired, instead of returning the discharge from the cracking passage-way to the same still in which the original vapor-ization occurred, such discharge may be run` off through the line 49 to another still for the coking of the residuum. i

It will thus be seen that in general the invention contemplates segregating out crackable constituents from a-hydrocarbon stock and passing these through a cracking zone,-

thence distilling the residuum to dryness in the manner of a coking still operation. In this way the usual carbon difficulties which beset the use of cracking apparatus in general are avoided as the hydrocarbons passing through the cracking zone have such high velocity that substantial deposit at this place is prevented and Acarbon deposit occurs in the final coking still zone where the construction of the apparatus is such as to make possible the handling of carbon to the best advantage. Moreover, it will be noticed that relatively little or in some cases no external heat on the coking still is required as the temperature of the discharge from the cracking passage-way is relatively high and external heat is necessary generally only at the initial distillation in preparing the, crackable stock. By introducing the discharge from the cracking zone so as to passfrom the perforations of the bottom pipe 48 and impinge upon the floor of the still a certain scouring action is exerted thereon and sufficient agitation is secured also to keep the carbon mass from settling down until relatively late in the run. Afpressure release valve R in the cracking passage-way discharging line permits of the separate adjustment and control of pressurein the cracking zone to the extent that such may be desirable or necessary.

Connections as at 5l and 52 leading to the accumulator tanks may be provided, in order to admit condensates from towers of other stills, or any other stock, for cracking if desired.

While I have described my invention with reference to certain particularities of detail, it will be understood that this is for the purpose of illustration to make the invention' clear, rather than being limitative in character, and the invention is to be considered as limited only as defined in the following claims in which it is my intention to claim all inherent novelty as broadly as the prior artpermits.

lVhat I claim is 1. Apparatus of the character described which comprises a still, a series of fractional condensers for receivin vapors from said still, a final cpndenser or receiving vapors from the fractional condensers, connections from the fractional condensers back to the still, accumulator tanks for receiving condensate from the fractional condensers, cracking passage-Ways, connections for passing condensate from each accumulator tank separately to each cracking passageway, and discharge lines from the cracking passage-ways connecting into a perforated pipe in the bottom of the still first mentioned.

2. Apparatus of the character described which comprises a still, a series of fractional condensers for receiving vapors from said still, connections from the fractional condensers back to the still, accumulator tanks for receiving condensate from the fractional condensers, cracking passage-ways, connections for passing condensate from each accumulator tank separately to each cracking passageway, and discharge lines from the cracking passage-ways -connecting into a perforated pipe in the bottom of the still first mentioned.

3. Apparatus of the character described which comprises a still, a series of fractional I from the upper portion of each tower to the lower portion of the next adjacent tower cracking passage-ways, receptacles for condensate that is to be withdrawn from the system, condensate accumulator tanks, connections therefrom to the cracking passageways, and connections from the lower portion of each tower to the still, to the receptacles, and to the accumulator tanks.

5. Apparatus of the character described,

comprising a still, a series of fractional condensers for receiving vapors from said still, a plurality of cracking passage-ways, means for selectively distributing fractions from -the condensers to the `cracking passage-ways, whereby the cracking conditions imposed on each fraction may be adjusted in accordance with the requirements of that fraction, said means comprising receiving tanks for said fractions and individual pipe connections to each crackin passageway, and connections from the crac 'ng passage-ways to the bottom of the still. f

6. Process for converting hydrocarbon oils,

comprising distilling a body of the oil, passing vapors formed thereby through a series of fractional condensation zones, accumulating separate bodies of condensate from such condensation zones, simultaneously cracking such bodies of condensate in separate cracking zones, and passing the cracked product into the body of oil undergoing distillation.

7 Process 4for converting hydrocarbon oils, comprising passing vapors formed by distilling a body thereof through a. series of fractional condensation zones, accumulating a body of heavy condensates from the first zonesof such series, accumulating a body of lighter condensates from later zones of such series, cracking such bodies of condensate in separate cracking zones, and simultaneously passing the eiuent from both cracking -zones. into the body of oil undergoing distillation.

8. Process according to claim 7, in which the operation is continued until the body of oil undergoing distillation is substantially converted into coke. p

LOUIS LINK. 

